Hi @nannuabhi. Did you find an answer for this last issue? I’m also experiencing 403:s after having fixed that CSP issue.
@Eventyret, do you have any insight in this? My S3 is configured the exact same way as recommended in all guides I can read (this one for instance). The app is using the aws access id + access key of the IAM user who is the creator of the bucket. Uploading works just fine.